Ok, this is a question i got in test and bought it here for some smart person to answere. Please explain why This would be the best answere:


This is a snapshot of what the system gave to me as result of the
TOP command in the red hat enterprise linx command line.

::::::::::::::::::::::::::::::::::::::::::::::::::::::
top - 05:14:52 up 3 days, 12:34, 2 users, load average: 4.39, 1.40, 0.48
Tasks: 86 total, 79 sleeping, 7 running, 0 zombie, 0 stopped
Cpu(s): 20.0%us, 79.8%sy, 0.4%ni, 0.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 255184k total, 247244k used, 7940k free, 91620k buffers
Swap: 521632k total, 20756k used, 500876k free, 67012k cached
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::
Q1. Roughly how much physical memory is being devoted to processes, in megabytes?
A. 255 - 92 = 163
B. 255 - 8 = 247
C. 255 - 67 = 188
D. 255 - 92 = 163
E. 255 - 8 - (92 + 67) = 88
The answere is actually E, BUT WHY IS IT E?



Question 2:
Roughly what percentage of the machine's physical memory is devoted to caching I/O operations?
A. 5%
B. 10%
C. 25%
D. 33%
E. 60%
the correct one is E but why is it 60 percent?
:::::::::::::::::::::::::::::::::::::::::::::::::::;;;;;
root@station root]$ uptime
05:06:00 up 3 days, 12:25, 2 users, load average: 0.89, 3.25, 8.87
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
Refer to the information on the top using the command uptime.


question 1:
Which of the following best describes the activity of the machine?
A. The machine has recently been active, but is currently inactive.
B. The machine has recently been inactive, but is currently active.
C. The machine has been and continues to be active.
D. The machine has been and continues to be inactive.
E. None of the above
The correct one is A. buut why?


The last on also refers to the exhibit listed above.


Questions 2.:


2.

How long has passed since the machine was most recently booted?
A. 5 hours
B. 8.87 hours
C. 12 hours
D. 2 hours
E. 84 hours
The correct one is E why?

How can it be 84 hourse if every thing is in minutes. It has been up for 3 days? well thats 3 times 24 right? so that is equal to 72 hourse for 3 days. The machine has been running since then so why is this last question E say 84 instad of 72?

uptime: its all the fields until a new field name (users) appears....
BTW, please use code tags when posting tech info https://www.linuxquestions.org/quest...do=bbcode#code

hello, as i said i know what the uptime command does.
I just want to know why the ansere of one of the questions i 84 hourse. The one where it asks the user:


how long has it been since the machine has last booted?


also this one:

What type of work is the machine doing? looking at the users, cpu timing and it's percentages how would we identify if the system is performinh numerous calculations or performing many input and out put tasks or both? It's by looking at the users? cpu or meminfo?
Thanks in advnace
Raaghav./

Free memory (8) is not "devoted to processes". Depending on your point of view buffers+cache (92+67) is either mostly not or entirely not "devoted to processes".
So given that limited data, the amount devoted to processes is the total minus the specific parts of that total which are disjoint and not devoted to processes.

Did you think some answer other than E was correct? If so, why?
Caching I/O is most of buffers plus most of cache. Those add up to 62% of the total. Since it is a multiple guess (not free response) quiz, you select 60%.

The 20%us and 79.8%sy shows the CPU is completely in use at the moment.

I think the load average info is typically bogus anyway and I forget what units it is in. So possible something about past activity can be deduced from that, which I am missing. So far as I understand, it measures some process queuing information that doesn't actually correlate well with any sensible definition of usage level.

The 79.8%sy stands out as the unusual and key factor in that question. But what exactly it means is less clear.

Obviously it indicates the CPU usage is not dominated by user mode calculations. It is dominated by kernel work. We can assume that kernel work is in response to use mode requests. But within that, there are too many possibilities.

One possibility is that the user mode processes are making a lot of I/O requests that are being almost all satisfied from buffers/cache so the CPU is never stalled waiting for physical I/O.

At least pretend to be willing to put some thought or effort into this.

Look at the answer you were given, that you seem to be rejecting. It is the answer to your question. Think about what chrism01 said until you understand how it is your answer.

hello thanks people for hhelp. now i undertsand .

no worries!
you may cloe this thread?

Nope. If you're happy with the answers given to your questions, you can mark the thread as SOLVED (see at the top of your first post). On the other hand threads at LinuxQuestions stay open to let other users post their add-on (if any).

Ok listen as you said the following about uptime command in linux:

Why is that equal to 84 hours. Iv treid this adding 24*3 because there is 24 hourse in a day and if it states there is 3 days then it should be 72 hourse altogether not 84 hours?

Read that carefully and it'll become clear

Maybe we are being unfair to a non native speaker of English.

The word "plus" is implied when you say or write that in English.

"3 days, 12:34" means three days plus twelve hours plus thirty four minutes.

That is closer to 85 hours than to 84. But in a multiple guess test, it doesn't pay to over think such details.